For a two-stroke stepped-piston engine, scavenging system played an important role in determining the performance of engine. A study had been made in order to enhance the scavenging system of current existing single cylinder two-stroke stepped-piston engine that has established in Automotive Development Centre (ADC), Universiti Teknologi Malaysia (UTM). This study had applied the use of SolidWorks integrated with COSMOS FloWorks 2012 as a simulation tool throughout the project. This is a static condition model test where piston is located at BDC with the flow pattern and velocity vector distribution in cylinder were the criteria of evaluation of performance. The parameters that had been playing around were the various upsweep angle and tangential angle of scavenging ports and thus, the outcome of this evaluation is then the scavenging ports design with better a configuration compared to the existing engine model. After all, the final engine configurations that obtained from analysis were upsweep angle of main port at 75°, upsweep angle of auxiliary ports at 50° and tangential angle of auxiliary port at 40°. This enhancement of scavenging system will perform a better scavenging efficiency, reduce emission of unburned hydrocarbons and overcome the short-circuiting problem of single cylinder two-stroke stepped-piston engine.